Thermostat for electric heaters.



L maximum THERMOSTAT FOB BLEOTBIO HEATEBB.

,APPLIOATIOI EILBDJAI. 2. 190B.

Patented Nov; 10,1908. l

XXI L UNITED STAWENT OFFICE.

H. RICHARDSON, OF ONTARIO, CALIFORNIA, ASSIGNOR TO PACIFIC ELECTRIC HEATING l COMPANY, OF ONTARIO, CALIFORNIA, A CORPORATION 0F CALIFORNIA.

THERMOSTAT FOB ELECTRIC ULTIM.'

Bpeeieatdon of Letters Patent.

nteated'sev. 1o, isos..

Appuaaen mea :mw-y a, im. saw le. secon.

To all .whom i! may concern: 4

Be itknown that I, EARL H. RICHARDBON, a citizen of the United States, residing at Ontario, in the county of San Bernardlno and State of California, have invented a newand -useful Thermostat for Electric Heaters, of

which the following is a specification.

This invention relates to electric heaters and particularly to a device for automatically opening the circuit through the heating element of the heater when the temperature rises to a certain point, whereby damage from overheating the parts of the heater or articles in contact with the heater is avoided.

One object of the invention is to dispense with extra circuits and provide a simple and direct acting device for automatically openmg the main or heating circuit at any desired degree of temperature within the capacity of the device.

Anotlier object is to provide means for regulating the device from without the walls of the heater.

Another object is to rovide a novel'form o'f temperature operatedl controller.

Another object is to arrange the temperature o pekated controller out of the circuit so that it isunaiected by the current.

Another ob'ect is to compel the closing of the circuit bylian'd after the automatic open- ).ngntihereof.

s device is of especial advantage for use 1n electric laundry irons and in the accompanymg drawings I have shown the device m such capacity.

Referring to the drawings; Figure l is a vertical, longitudinal section throu h a launiron, the view being takenon of 2. Fiis a sectional view taken on line z of tional 'view on of 1. Fig. lis' a plan view of the temperature'operated-detent. Fig. 5 is a perspective view| d the manual switch controlling and regulating device. Fig. .6 is an cross section taken on the same planeas Fig. 3, showing the manner of attaching the'contact blades to the bracket The walls of the laundry iron comprise a bottom portion 1 provided with a sole 2 and a cover 3 which is removabl secured by screws 4 to the bottom portion A heatinsulating material, com rising asbestos 5, is arbetween e lower portion 1 and 55 cover 3,as shown, and a layer of mica 6 is 1. Fi 3 is a vertical ser;

also preferably employed directly underneath the asbestos 5. The lower 'portion 1 is hollow as shown and arranged therein are two heating elements, each comprising a core 7 with its e'nds secured in any desired manner to the lower portion 1, and each core iswound with resistance wire 8. As'clearly shown in Fi 2, the two heating elements are angular y disposed to each other, their front ends be' arranged close together and' the heating e ements diverging toward the rear. The

rear ends of wires 8 are connected with terminals 9 which extend throu h the rear wall of the lower ortion 1, and wghich may be of any referre construction. As shown the terminals are provided-with contact biades shown.

Secured to the under side of the cover 3 by a screw 11 is a supporting bracket 1-2. .The supportin bracket 12 extends down between the two eating elements near their front ends. Each core 7, as shown in Fig. 3, is triangular in cross section, and at the ront ends of the cores 7 suiiicient space is afforded between them for the bracket12 and parts carried thereby, so that the wire on core 7 is out -of contact with the bracket'12 and arts carried thereby' this feature is clear y shown in Fig. 3 winch is a sectionalview aken through the forward ends of the cores. The wire-wound cores 7 are insulated from the bottom wall of the lower portion 1 by laye of mica 13.

Secured to both sides vof the bracket- 12 and extending rearwardly therefrom are :two contact blades 14 and 15, the rearends of each be` curved to a circular arc. Each contact b ade is'insulated from the bracket 12 by' a layer of mica 16.- Screw bolts 17 and 18 pass through both blades 14 and 15 and secure them 'to the bracket 12. As clearly shown in Fig. 6, the blade 15 has an enlarged hole passes, and a mica washer 20 insulates the nut of bolt 18 from blade 14 ,which enlarged hole 19 revente contact oi blade 15 with of bolt- 17. Thebracket 12 1s likewise provided with a l prevents contact o f bolt 1 therewith, but

.l'for the attachment of the switch plug, not l 19 through which the bolt 17 ioo e hole 21 which the blade14'has contact with bolt 17, there y washer 22 between the of t' bolt'and tlle'blade 15. Blade 15 1s in contact withbolt'lsand blade 14 is out of contact with bolt 18 by means of a similar construction, the blade 14 and bracket 12 each ha an enlarged hole not seen, thro h which the shank of bolt 18 passes and t e head of bolt 18 being in contact with blade 15 through the medium of awasher 23. Bolt 18 is connected by wire 24 with the wire on one of the heating elements while bolt 17 is connected b a wire 25 with the wire on the other heating element thus blade 14 is in connection with oneoi the heat' elements and blade 15 isin connection wit the other heating element.

Blades 14 yand 15 form a 4part of the switch for controlling the circuit and movablevbetween blades 14.and 15 is a plugl 26v mounted` on a stem 27. The lower en of the stem 27 has a flange 28 forming an abutmentand the u per portion of stem 27 is slidably moun in a nip le 29 which is screwed to the cover 3. cover`3 is a bail30 having a handle 31,'the front portion of bail 30 being secured to cover 3 by screw 32, while-nipple 29 has a il e 33 which serves to secure the rear portion of bail 30. The stem 27 is slidable vertically to move the plug 26 into or out of contact with blades 14 ,and 15, and the lower portion of plug 26 is beveled, as

shown' to enable the lug to be easily slipped down between that des 14 and 15 in c 0S- ing the circuit.' The blades 14 and 15 are spring blades in order to insure good con- Atact with the pl 26 and upon retraction of 26 from t blades they- :ring toget,

r somewhat thus the lbevel portion tween the blades 14 and l5. Attached to the upper end of stem 27 isa knurled knob 34 having a hub 35 to which is secured a sleeve 36, the lower end of sleeve tween the upper end of mpple 29 and lub 35' and serves to move the stem 27 and plug 26- up when released by the tem rature opervated detent about to be descri d.

As clearly shown in Fig. 4',- the flange 28 -on the lower en d of the stem-27 is aduated ped hke a cam, and un er no con tions the shoulder 28 is by a temperature controlled detent 38 which comprisestw'o blades 39 and 40 formed ofmaterials ha .65

o ving different coelcients of expansion. For example, blade 39 is formed -of brass, and blade 40 is formed of steel. The two blades may be fastened to ther permanently Ain any-desired manner, or ex- 4 L(so,

this hooked grtion' of amlple, by n veting, as shown. The rear end of lade 40 is bent over the end of blade 39 asshown, topr'etect the endef blade-39, and the steel blade 40 may preferably. as it is 'the part astened to the of pluge 26, enables it to 'be easily' pushed` down blad in Fig. 4, on account of the difference in the ceilicients of expansion of the two metals, the brass blade 39 having a tendency to elongate more rapidly than the steel blade 40 and thus causing a AWai' ing action to be given to the detent as a wliole. As the detent thus bends itsouter end moves away from the stem 27 and closer to the outer rim ofthe shoulder 28 and at a certain temperature the detent will move entirel free from the edge of the shoulder 28, the release of the shoulder by the detent being determined by the angular position in which the shoulder 28 is set. For example, as shown in Fig. 4, the shoulder 28 isset so that a very high lde gree of temperature will be required to bend.

the detent 38 sufficiently to release lthe shoulder, while by turning the stem 27 a. narrower portionv ofy -'the shoulder Lwill be brought into contact with the. detent 38 and release will be effected at a less temperature.'

adual variation inthe By reason of the width of the shoul er 28 the same may be set to'release at any desired degree of temperature within the limits under which the eater is used in Practice.

U n release o the shoulder 28 bydetent 38 t e spring 37 pressing against the hub 35 forces up the stem 27 and removes the lug 26 from contact with the plugs 14 an 15 thereby breakin the circuit, and the circuit i will remainbro en and the heater will be inoperative and will gradually cool until the operator again closes the circuit, which is done by sim ly pushing down on the'thumb iece 34. e

. stem 27 is thus moved own, the llower beveled portion of llange 28 rides over the edge ofthe rear end of detent 38 until the detent 38 snaps over the shoulder 28, therebyV again locking the switch` closed and rendering the heater operative. It. should be noted that no current passes through the detent 38 and that its life is thus not impaired. The sleeve 35 may be provided with indicating numerals, as shown in Fig.` 5 in order that the knob '34 may be turned to est the shoulder 2s in desired osition accordingto .the temperature at w ich the circuit is to be broken, which temperature will, obviously,- in ordin casesv be above the temperature require for work and belowthe temperature which would be in'uiious. A

t I claim is.;- 1. In lmbination, an ment, a circuit therefor, a air of terminal es for thecircuit, a ug movable bef tween the blades to close tl'l) e circuit, the plug `having der, and walls inclosing said closing the same, a su porting bracket ex? a tgraduated shoulder, a tem erature operated etent normally engaging t e shoulelements, and means for adjusting the position of the graduated shoulder with respect to the detent.

2. In combination, an electric heating element, a circuit therefor, temperature operated means for brealn'ng said circuit comprising a detent, a graduated shoulder normally engaged by the detent, a stem carrying said graduated shoulder, a knob on the stem for tumin the stem, and ad'usting the graduated oulder, the knob aving indicating marks.

3. In combination, a pair of rearwardly diverging heating elements, a hollow bodyintending between the orward ends of the heating elements, a pair of contact blades projecting rearwardly from the supporting rackets, each, blade electrically connected with va heating unit, atemperature operated detent blade extendin rearwardly from the bracket, a plug norm y lying between the contact blades and closing the circuit, a stem carrying the plug and having an abutment engaged by the detent, and spring means exerting lo tudinal ressure on' the stem to move the ug out o l contact when the abutment is eased b the detent.

4. In combination, a hol ow body, a lpair of heating units therein, a removable cover on the body, a supporting bracket depending from the cover, a pair of contact blades between the heat' units and supported by said bracket, eac blade being eectrically connected with a heating unit, a temperature operated detent blade attached to the the contact blades, the stem aving an abutment normally by the detent blade and spring means su ported by the cover and exerting an upwar pressure on the stem.

5. In combination, a hollow bod a pair of heatin units therein, a remova le cover on the bo y, a supportin bracket depending from the cover, a pair o contact.blades be# tween the heatinglunits and supported by said bracket, eac blade eectrically connected with a heating unit, a temperature operated detent blade attached to the bracket and extending between the heating units, a niplple inthe cover, a stem slidable in the ni p e, a sleeve above the cover secured to t e stein, a knob on the stem, a coil spring within the sleeve between the nipple and knob, a plug on the stem normall lying between the contact blades, the stem aving alli ibutment normally engaged by the detent 6. In combination, a hollow bod a pair of liatici. units therein, al.) renlov le cover ont e y, a su port' rac et e nding from the cover, al.) pairud contact bliidaes between the heat' units and sup rted by said bracket, eac blade being tiically connected with a heating unit, a tem rature operated detent blade attached to g the bracket and extending between the heating units, a ni ple in the cover, a stem slidable and,revolu e in the nipple, a sleeve above the cover secured to the stem, a knob on the stem, a coil spring within the sleeve between the ni ple and knob, a plug on the stem normally ying between the contact blades, the stem' having a graduated abutment normally engaged by the detent blade.

In testimony' whereof I have hereunto set my hand at ontm', ottici-nia this 24th day of December 1907. J

EARL H. RICHARDSON.

In presence of- T. E. Panxn, C. V. Sm'm. 

